The present invention relates generally to magnetic devices for electronic circuits, and more particularly to devices such as inductors and transformers for mounting on circuit boards.
Conventional magnetic devices such as inductors and transformers typically include one or more conductive windings positioned about a bobbin or other winding mandrel. The windings may include primary and secondary windings in a transformer and one or more windings in an inductor. Magnetic devices of this nature are generally constructed with one or more terminal pins configured to be inserted through corresponding terminal holes, or vias, in a printed circuit board. The terminal pins project outwardly from a bobbin structure in many conventional configurations. The conductive windings positioned on the bobbin are electrically connected to the terminal pins such that the windings may be electrically coupled to electrical circuit traces on the printed circuit board after installation of the magnetic device on the circuit board. Each terminal pin generally extends through a via, or hole, in the circuit board; and a soldered connection is established using conventional soldering techniques.
In many circuit applications, it is desirable for one or more terminal pins on a bobbin to be electrically interconnected to other terminal pins protruding from the same bobbin. Conventional configurations for achieving electrical interconnection of terminal pins on a magnetic device bobbin typically include either providing jumper or crossover wires on the bobbin itself or providing one or more jumper or crossover traces on the main printed circuit board upon which the magnetic device is mounted. Such jumper wires may be used to connect pins on the same bobbin rail, or may be used as crossover connections to connect pins on opposing bobbin rails. The conventional solution of placing one or more jumper or crossover wires between pins on the bobbin structure itself is cost and labor intensive. Jumper and crossover wires of this nature may also become dislodged or may become damaged during installation and use. Additionally, thermal, RF or magnetic effects near external jumper and crossover wires on the bobbin may reduce performance of the device.
The second conventional solution of placing jumper or crossover traces on the main printed circuit board for electrically connecting bobbin terminal pins also has problems. For example, a printed jumper or crossover trace configuration is typically unique to a particular application for a specific circuit performance objective associated with a specific magnetic component. When a printed circuit board is configured with a printed jumper or crossover trace configuration for a specific bobbin terminal pin interconnection layout, the main circuit board is generally only operable for use with that particular magnetic device configuration for that specific circuit performance objective. The unique jumper or crossover trace configuration on the main printed circuit board limits the interchangeability of the main printed circuit board and prevents the main printed circuit board from being used with other transformers. Once a main printed circuit board is printed with a specific jumper or crossover trace configuration for connecting bobbin terminal pins, the jumper or crossover trace configuration is fixed. As a result, multiple circuits that may have similar features except for the bobbin pin jumper or crossover trace configuration require numerous different main printed circuit board layouts and require numerous boards to be printed with each unique jumper or crossover trace configuration to work with different magnetic components.
What is needed then are improvements in magnetic components to allow improved jumper and crossover connections.